In general, a display device such as PDP, CRT, LCD, and the like is equipped with an anti-reflection film (or an anti-glare film) for minimizing reflection of light entering the screen from outside.
In the existing anti-reflection film, an anti-reflection layer is predominantly disposed on a light-transmitting base, and an anti-reflection layer with a triple-layered structure wherein a hard coat layer, a high refractive index layer with a thickness of 1 μm or more, and a low refractive index layer are sequentially deposited is widely used (for example, Japanese Laid-Open Patent Publication No. 2002-200690).
Recently, to simplify the manufacturing process, the high refractive index layer is skipped in the anti-reflection layer, and a double-layered structure wherein a hard coat layer and a low refractive index layer are deposited are commonly used. (for example, Japanese Laid-Open Patent Publication No. 2000-233467).
Further, to combine both anti-glare property and scratch resistance, an anti-reflection film equipped with an anti-glare had coat layer is used. In this regard, a technology of coexisting anti-glare property and light-transmittance by controlling the thickness of the anti-glare hard coat layer to 50-90% of the average particle diameter of light-transmitting particles for forming a mat has been suggested (for example, Japanese Laid-Open Patent Publication No. 1996-309910).
Meanwhile, an anti-reflection film is generally manufactured by a dry method or a wet method.
According to the dry method, material having low refractive index (for example, MgF2, SiO2, and the like) is deposited on a base film as a thin film by deposition or sputtering, or material having high refractive index (for example, ITO (tin doped indium oxide), ATO (tin doped antimony oxide), ZnO, TiO2, and the like) and material having low refractive index are alternatively deposited. Although the dry method may manufacture an anti-reflection film having strong interfacial adhesion, it is not commercially widely used due to the high manufacture cost.
Meanwhile, according to the wet method, a coating composition comprising polymer resin, an organic solvent, and the like is coated on a base film, dried and cured. And, the wet method is widely commercially used due to relatively low manufacture cost compared to the dry method.
However, since the wet method should separately conduct processes of forming each layer of a hard coat layer, a high refractive index layer and a low refractive index layer, and the like included in the anti-reflection film, the manufacturing process is complicated, and interfacial adhesion is weak.
Thus, studies are actively progressed on an anti-reflective coating composition capable of forming 2 or more layers by single wet coating.
However, since phase separation is not smoothly achieved by coating of a composition, many problems including deteriorated function as each layer still exist.